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Scientists participating in the worldwide effort to develop magnetic fusion energy for generating electricity gave progress reports to the 2013 annual meeting of the American Association for the Advancement of Science in Boston. Speaking were physicists George "Hutch" Neilson of the U.S. Department of Energy's Princeton Plasma Physics Laboratory, and Richard Hawryluk, deputy director-general of the ITER Organization. Following are summaries of their presentations.

Previewing the next steps on the path to a magnetic fusion power plant

By John Greenwald

Scientists around the world have crossed a threshold into a promising and challenging new era in the quest for fusion energy. So said Advanced Projects Director Hutch Neilson in remarks to the 2013 annual meeting of the American Association for the Advancement of Science in Boston.

The new phase has begun with the construction of ITER, Neilson said during his talk on February 16. With construction of ITER under way, many national fusion programs "are embarking on their own projects to demonstrate the production of electricity from fusion energy," Neilson said.

These nations are considering "DEMO" programs that would mark the final step before the construction of commercial fusion facilities by midcentury. Such programs have brought worldwide researchers together to discuss common challenges in annual workshops that the International Atomic Energy Agency began sponsoring last year. "The scientific and technical issues for fusion are well known," said Neilson, "but the search for solutions is extremely challenging."

The key issues entail developing an understanding of and solutions for:

Plasma confinement and control.

Plasma power exhaust.

Power extraction and tritium self-sufficiency.

High availability for generating electricity.

Individual countries are exploring their own paths to a DEMO, based on their perceived need for such energy. All such plans remain tentative and subject to government approval.

A look at the possible roadmaps that countries are considering:

China—The world's most populous nation is pushing ahead with plans for a device called China's Fusion Engineering Test Reactor (CFETR) that would develop the technology for a demonstration fusion power plant. Construction of the CFETR could start around 2020 and be followed by operation of a DEMO in the 2030s.

Europe and Japan—These programs are jointly building a powerful tokamak called JT-60SA in Naka, Japan, as a complement to ITER. Plans call for construction to be completed in 2019. The Japanese and Europeans will then pursue similar but independent timelines. Both could start engineering design work on a DEMO around 2030, following the achievement of ITER milestones, and placing the DEMO in operation in the 2030s.

India—The country could begin building a device called SST-2 to develop components for a DEMO around 2027. India could start construction of a DEMO in 2037.

Korea—The program plans to build a machine that it calls K-DEMO that would develop components in the first phase, called K-DEMO-1, and utilize the components in the second phase, or K-DEMO 2. Construction could commence in the mid-to-late 2020s, with operations starting in the mid-2030s.

Russia—The country plans to develop a fusion neutron source (FNS), a facility that would produce neutrons, the chief form of energy created by fusion reactions, in preparation for a DEMO. The FNS project is part of a Russian commercial development strategy that runs to 2050.

United States—A next-step Fusion Nuclear Science Facility (FNSF) is under consideration. It would be used to investigate materials properties under fusion conditions, and develop components for a DEMO. Construction of the FNSF could start in the 2020s.

Neilson concluded his talk by noting, “There are multiple approaches to fusion development but broad agreement on the goals, critical tasks and value of international collaboration.”

ITER: Integrating fusion science and technology

Richard J. Hawryluk, Deputy Director-General, ITER Organization

ITER is a large-scale scientific experiment intended to prove the viability of fusion as an energy source. ITER is currently under construction in the south of France. In an unprecedented international effort, seven partners—China, the European Union, India, Japan, Korea, Russia and the United States—have pooled their financial and scientific resources to take fusion energy to the threshold of industrial exploitation. ITER will not produce electricity, but it will resolve critical scientific and technical issues and thereby take fusion to the point where industrial applications can be designed. By producing 500 MW of power from an input of 50 MW—a “gain factor” of 10—ITER will be the proof of principle for magnetically-confined burning plasmas that opens the way to the next step: a demonstration fusion power plant.

The ITER fusion machine is a “tokamak”-type reactor (Russian acronym for “toroidal chamber and magnetic coils”) relying on confining the plasma with a strong magnetic field. On-site construction of the scientific facility began in 2010. The project has made the transition from design to fabrication of large-scale mockups and components, in addition to construction of buildings. Beginning in 2014 the components will be shipped from their manufacturing sites in the four corners of the world to the construction site in France, where they will be assembled into the ITER device.

ITER is one of the most complex scientific and engineering projects in the world today. The complexity of the ITER design has already pushed a whole range of leading-edge technologies to new levels of performance. As will be discussed, innovative solutions are being developed to address specific ITER challenges. However, further science and technology are needed to bridge the gap to commercialization of fusion energy.

The completion of the construction of the ITER facility will enable the detailed study of magnetically-confined burning plasmas. This is an experimental regime, which is not accessible in current facilities. Previous experiments on the Tokamak Fusion Test Reactor (TFTR) in the US and the Joint European Torus (JET) in the UK studied low-power burning plasma experiments with a “gain factor” of <1. These pioneering experiments identified interesting and important scientific issues, which can only be fully explored on ITER due to the strong interaction of the self-heating mechanism with the background plasma. The relationship of the previous pioneering experiments on TFTR and JET to burning plasma issues to ITER will be highlighted in the presentation.

BACKGROUND TO THE ITER PROJECT

ITER—designed to demonstrate the scientific and technological feasibility of fusion power—will be the world's largest experimental fusion facility. Fusion is the process which powers the sun and the stars: when light atomic nuclei fuse together to form heavier ones, a large amount of energy is released. Fusion research is aimed at developing a safe, abundant and environmentally responsible energy source.

ITER is also a first-of-a-kind global collaboration. Europe will contribute almost half of the costs of its construction, while the other six Members to this joint international venture (China, India, Japan, the Republic of Korea, the Russian Federation and the USA), will contribute equally to the rest. The ITER project is under construction in Cadarache, in the south of France.